Solution to:
Zebra

The answer: the German.

The Norwegian lives in the leftmost house (which we will call house number 1) and next to the blue house, so the blue house is house 2.

The green house (left of the white house) is house 3 or 4 and the white house is 4 or 5.
In the house in the middle (house 3), they drink milk and in the green house, they drink coffee,
so the green house is house 4 and the white house is house 5.

Now we know the following:

House 1

House 2

House 3

House 4

House 5

Color

blue

green

white

Owner

Norwegian

Pet

Beverage

milk

coffee

Occupation

We do not know the colors of houses 1 and 3 (red or yellow) yet.
The Norwegian lives in the leftmost house and the Brit lives in the red house,
so the Brit lives in house 3 (red) and the Norwegian lives in the yellow house (house 1).

In addition, we know that the fireman lives in the yellow house (where the Norwegian lives) and that in the next house (house 2) there must be a horse.

House 1

House 2

House 3

House 4

House 5

Color

yellow

blue

red

green

white

Owner

Norwegian

Brit

Pet

horse

Beverage

milk

coffee

Occupation

fireman

The Dane drinks tea, so the Dane can only live in house 2 or 5.
The bus driver drinks lemonade, so also he can only live in house 2 or 5 (but not in the same house as the Dane).
The water must therefore belong to house 1.

Because they drink water in the house that lies next to the house where the baker lives, the baker lives in house 2.
The bus driver and the lemonade therefore belong to house 5, and the Dane and the tea belong to house 2.

House 1

House 2

House 3

House 4

House 5

Color

yellow

blue

red

green

white

Owner

Norwegian

Dane

Brit

Pet

horse

Beverage

water

tea

milk

coffee

lemonade

Occupation

fireman

baker

bus driver

The German is plumber and must therefore live in house 4. The postman and the birds belong to house 3.

The cats are in the house next to the house where the baker lives, which must be house 1.

House 1

House 2

House 3

House 4

House 5

Color

yellow

blue

red

green

white

Owner

Norwegian

Dane

Brit

German

Pet

cats

horse

birds

Beverage

water

tea

milk

coffee

lemonade

Occupation

fireman

baker

postman

plumber

bus driver

The Swede and his dog must live in house 5. We conclude that the German owns a zebra.